Developmental biology. A scar is born: origins of fibrotic skin tissue

Selenium-Albumin Nanoaccelerator Hydrogel Promotes Wound Healing by Antibacterial, Anti-Inflammatory and Antioxidant along with Inhibits Scar Formation via Downregulating CD36

Wounds repairing after skin damage or diabetes remain a vast medical challenge, which often faces infection, inflammation, oxidative stress, and skin scarring. Herein, a multifunctional selenium-albumin nanoaccelerator hydrogel (H-Se NPs-Gel) is constructed based on the self-assembly of human serum albumin (HSA) with selenium nanoparticles (Se NPs) using carbomer as the carrier, it has remarkable antibacterial, anti-inflammatory, antioxidant and inhibits scarring properties than Se NPs for wound healing. Compared with Se NPs, H-Se NPs exhibit smaller particle sizes, exceptional stability, better antibacterial activity against common bacteria and MRSA, and superior antioxidant and anti-inflammatory capabilities in vitro without remarkable toxicity on skin cells. Importantly, it exhibits superior efficacy to Se NPs-Gel in accelerating the healing of full-thickness skin defects and diabetic wounds in mice. Interestingly, in a hypertrophic scar (HTS) model, H-Se NPs-Gel is more effective than Se NPs-Gel in inhibiting collagen formation to suppress scarring, which is mediated by the inhibition of CD36. The antagonistic effect of H-Se NPs on CD36 is also proved with the CD36 overexpression model. Furthermore, H-Se NPs-Gel demonstrates excellent safety in mice without systemic toxicity. H-Se NPs-Gel is an effective and safe therapy strategy for promoting wound healing and reducing scar formation in clinic.

Thyroid Cancer and Fibroblasts

Thyroid cancer is the most common type of endocrine cancer, and its prevalence continue to rise. Non-metastatic thyroid cancer patients are successfully treated. However, looking for new therapeutic strategies is of great importance for metastatic thyroid cancers that still lead to death. With respect to this, the tumor microenvironment (TME), which plays a key role in tumor progression, should be considered as a new promising therapeutic target to hamper thyroid cancer progression. Indeed, thyroid tumors consist of cancer cells and a heterogeneous and ever-changing niche, represented by the TME, which contributes to establishing most of the features of cancer cells. The TME consists of extracellular matrix (ECM) molecules, soluble factors, metabolites, blood and lymphatic tumor vessels and several stromal cell types that, by interacting with each other and with tumor cells, affect TME remodeling, cancer growth and progression. Among the thyroid TME components, cancer-associated fibroblasts (CAFs) have gained more attention in the last years. Indeed, recent important evidence showed that thyroid CAFs strongly sustain thyroid cancer growth and progression by producing soluble factors and ECM proteins, which, in turn, deeply affect thyroid cancer cell behavior and aggressiveness. Hence, in this article, we describe the thyroid TME, focusing on the desmoplastic stromal reaction, which is a powerful indicator of thyroid cancer progression and an invasive growth pattern. In addition, we discuss the origins and features of the thyroid CAFs, their influence on thyroid cancer growth and progression, their role in remodeling the ECM and their immune-modulating functions. We finally debate therapeutic perspectives targeting CAFs.

3-D wound scanner: A novel, effective, reliable, and convenient tool for measuring scar area

This study aimed to investigate whether a three-dimensional (3-D) wound scanner could be used to measure the area of scars. Scar models were constructed using flesh-colored, brown-colored (simulating hyperpigmented scars), orange-colored (simulating scars with obvious vascularization), and white-colored (simulating hypopigmented scars) plastic. Each colored plastic was used to construct scar models with regular and irregular base surfaces (four each). Two human models were selected to simulate patients with scars, and the scar models were placed on the right cheek, right lower jaw-neck, right ulnar forearm, anterior tibial region of the right calf, and at the back of these human models for scar area measurement. Two experimenters separately measured the scar area vertically using the profile method, pixel method, and 3-D wound scanner. Each experimenter measured the scar area thrice. Regarding accuracy, we found significant differences between the data and standard value of various measurement methods (P<0.05); however, the ratio of the data and standard value using the 3-D wound scanner was 0.982, which was the closest to 1, and showed the lowest coefficient of variation. Regarding correlation, Spearman's coefficient using the 3-D wound scanner was 0.992, showing the strongest correlation. With respect to inter-experimenter reliability and stability of retesting, each Cronbach's coefficient of the 3-D wound scanner between the two experimenters was >0.90, showing high reliability; thus, fulfilling the requirements for clinical measurement. The 3-D wound scanner took an average time of 38.87±3.45s for measurement, which was significantly shorter compared that for other methods The 3-D wound scanner showed greater accuracy and correlation, and a shorter measurement time, compared with other measurement methods The inter-experimenter reliability and retesting stability of the 3-D wound scanner also fulfilled the requirements for clinical measurement.

Fibroblasts in the Tumor Microenvironment: Shield or Spear?

Tumorigenesis is a complex process involving dynamic interactions between malignant cells and their surrounding stroma, including both the cellular and acellular components. Within the stroma, fibroblasts represent not only a predominant cell type, but also a major source of the acellular tissue microenvironment comprising the extracellular matrix (ECM) and soluble factors. Normal fibroblasts can exert diverse suppressive functions against cancer initiating and metastatic cells via direct cell-cell contact, paracrine signaling by soluble factors, and ECM integrity. The loss of such suppressive functions is an inherent step in tumor progression. A tumor cell-induced switch of normal fibroblasts into cancer-associated fibroblasts (CAFs), in turn, triggers a range of pro-tumorigenic signals accompanied by distraction of the normal tissue architecture, thus creating an optimal niche for cancer cells to grow extensively. To further support tumor progression and metastasis, CAFs secrete factors such as ECM remodeling enzymes that further modify the tumor microenvironment in combination with the altered adhesive forces and cell-cell interactions. These paradoxical tumor suppressive and promoting actions of fibroblasts are the focus of this review, highlighting the heterogenic molecular properties of both normal and cancer-associated fibroblasts, as well as their main mechanisms of action, including the emerging impact on immunomodulation and different therapy responses.

Cutaneous Scarring: Basic Science, Current Treatments, and Future Directions

Significance: Scarring of the skin from burns, surgery, and injury constitutes a major burden on the healthcare system. Patients affected by major scars, particularly children, suffer from long-term functional and psychological problems. Recent Advances: Scarring in humans is the end result of the wound healing process, which has evolved to rapidly repair injuries. Wound healing and scar formation are well described on the cellular and molecular levels, but truly effective molecular or cell-based antiscarring treatments still do not exist. Recent discoveries have clarified the role of skin stem cells and fibroblasts in the regeneration of injuries and formation of scar. Critical Issues: It will be important to show that new advances in the stem cell and fibroblast biology of scarring can be translated into therapies that prevent and reduce scarring in humans without major side effects. Future Directions: Novel therapies involving the use of purified human cells as well as agents that target specific cells and modulate the immune response to injury are currently undergoing testing. In the basic science realm, researchers continue to refine our understanding of the role that particular cell types play in the development of scar.

Expansion of CD26 positive fibroblast population promotes keloid progression

BACKGROUND

Keloid is a skin fibrosis disease that characterised by invasive growth of fibroblasts and aberrant deposition of extracellular matrix. Studies indicated that keloid fibroblasts (KFs) is a class of 'activated' fibroblasts, which show accelerated proliferation and excessive extracellular matrix formation as compared with normal fibroblasts (NFs). However, the mechanism underlying keloid fibroblasts dysfunction is still unknown.

OBJECTIVE

To verify CD26 expression difference between KFs and NFs, and investigate the function of CD26 positive fibroblasts in keloid progression.

METHODS

KFs and NFs were isolated from Keloid tissues and normal skin tissues respectively. Flow cytometry was performed to isolate CD26+/CD26- fibroblasts from KFs and NFs. Proliferation of different fibroblasts were analyzed by CCK8 assay and Ki 67 straining. Profibrotic phenotype difference was detected by qRT-PCR, western blot, ELISA and immunofluorescence. Scratching experiment and transwell assay were used to assess invasion ability of CD26+/CD26- fibroblasts. Diprotin A was used as a CD26 inhibitor to further investigated the function of CD26 fibroblasts in keloid disease.

RESULT

CD26 expression was increased in KFs, and the proportion of CD26+ fibroblasts was significantly increased in KFs. Cell viability analysis showed that CD26+ fibroblasts was more active in proliferation. Furthermore, the expression of profibrotic genes were increased in CD26+ fibroblasts, including TGF-β1, IGF-1, IL6, collagen 1, collagen 3 and fibronectin. And meanwhile, CD26+ fibroblasts showed stronger invasion ability as compared to CD26- fibroblasts. Moreover, Diprotin A significantly suppressed proliferation and extracellular matrix secretion of CD26+ fibroblasts isolated from keloid tissues.

CONCLUSION

Our findings suggest that CD26+ fibroblasts possess proliferation advantage in compare to CD26- fibroblasts, and the advantage caused expansion of CD26 positive fibroblast population promotes keloid progression.